1. Field of the Invention
This invention relates to a buttonhole device for a zig-zag sewing machine, and more particularly to a two-step buttonhole device wherein one bartack and one side stitch are produced in a first step, and the other bar tack and the other side stitch are produced in a second step.
2. Description of the Prior Art
In a zig-zag sewing machine, rotary shaft is operatively connected to a means by which lateral needle oscillation, needle position or base line and work feed are controlled, so as to produce one bar tack, one side stitch, the other bar tack, and the other side stitch of a buttonhole respectively at a first position, a second position, a third position, and a fourth position of the shaft. In order that the shaft may be automatically rotated from the first position to the second position, may be manually rotated from the second position to the third position, and may be automatically rotated from the third position to the fourth position, a two-step buttonhole device having a ratchet means and a cam means has been provided. However, the conventional two-step buttonhole device has difficulties such as the fact that the device is complex in construction and thepositions of the shaft are out of angular equidistance due to construction of the cam means. Consequently, indica corresponding to the positions of the shaft or four components of the buttonhole may not be shown equally spaced on a dial connected to the shaft.